Methylene Blue and Blood Transfusion in Hemorrhagic Shock Resuscitation: An Experimental Porcine Study.

Introduction: Hemorrhagic shock requires immediate treatment to prevent mortality and organ dysfunction. This study evaluates the efficacy of methylene blue (MB) with blood transfusion (BT) as a potential rescue therapy in acute severe bleeding in pigs.

Methods: Thirty animals were randomly assigned to one of six groups following the induction of fixed-pressure hemorrhagic shock, after reaching a mean arterial pressure (MAP) of 55 mmHg - Group 1 (60 BT: BT after 60 minutes), Group 2 (60 MB: MB infusion after 60 minutes), Group 3 (60 MB + BT: MB and BT after 60 minutes), Group 4 (15 MB + BT: MB and BT after 15 minutes), Group 5 (15 BT + 60 MB: BT after 15 minutes and MB infusion after 60 minutes), and Group 6 (15 MB + 60 BT: MB infusion after 15 minutes and BT after 60 minutes). Hemodynamic and blood gas parameters were meticulously recorded, reversal of the shock was considered when MAP reached 90% of the baseline MAP.

Results: Except for Group 2, all groups reverted from the shock. However, groups that received MB in combination with BT, specifically Groups 3 and 4, exhibited statistically significant higher ratios of maximum MAP to baseline MAP.

Conclusion: Using MB concomitant with BT allowed the reversal of hemorrhagic shock with higher median arterial pressure levels compared to BT alone or applying MB separately from BT. This suggests that simultaneous application of MB and BT could be a more effective strategy for reversing the effects of severe acute bleeding.